chore: migrate to python 3.13 and update dependencies

Migrate from Python 3.11 to 3.13 with updated dependencies. Switch from PyPDF2 to pypdf library for better PDF processing. Add new U14 age groups and extract-pdf utility script.

pyproject.toml

@@ -7,12 +7,12 @@ authors = [
 ]
 license = "MIT"
 readme = "README.md"
-requires-python = ">=3.11"
+requires-python = ">=3.13"
 
 dependencies = [
     "requests (>=2.32.3,<2.33.0)",
     "typer (>=0.15.1,<0.16.0)",
-    "pypdf2 (>=3.0.1)",
+    "pypdf (>=6.0.0)",
     "rl-ai-tools >=1.9.0",
     "fastapi[standard] (>=0.115.11,<0.116.0)",
 ]